Entheogens: Substances which generate god or spirit within. Peyote or psilocybin mushrooms are traditional examples of this. However, entheogenic use can involve the use of various other psychedelics and psychoactives, such as ketamine, dextromethorphan, DMT, and even non-psychedelic drugs if used in a religious or spiritual context.
Entheogens are not a category of drugs per se, but more a method of using them.